[Simultaneous use of carbohydrates and amino acids during total ischemia in the isolated rat heart (author's transl)].

The simultaneous utilization of carbohydrates and amino acids in the metabolic response to oxygen deprivation was studied i the isolated rat heart initially perfused according to Langendorff and submitted to periods of 2, 5, 10 and 15 min of complete ischemia. The results of the measurement of metabolite contents showed : (1) an immediate decrease of glycogen, pyruvate, alpha-ketoglutarate and aspartate; (2) a delayed decrease of citrate and glutamate; (3) an immediate and continuous increase of lactate and succinate; (4) a delayed increase of alanine; (5) a transient increase of malate + fumarate. The end products of anaerobic metabolism are lactate, which is an index of glycolytic activity, and alanine and succinate, which are indexes of amino acid fermentation. Succinate originates from aspartate, and alanine originates from glutamate. The amino acid pathway does not seem of importance in the production of ATP compared to glycolysis. However, its eventual role and the physiological implication of these reactions in the resistance of strict aerobic organisms to oxygen deprivation are discussed.